"Let's move on to something more productive, like discussing how we'd go about building a full-range MANTARAY horn that loads down to 40 Hz, yet keeps it's upper HF response!

Now THERE'S a challenge!"

Greets!

Indeed! It's strictly a sci-fi 'pipe dream' until either Mother Nature modifies the current physical laws or mankind figures a way to 'bend' them enough to make a suitable driver. In the meantime, a huge four way version of TD's Unity concept could come 'close enough' to covering ~16 - 22 kHz IMO.

GM